This invention relates to a linear cable-connector, and more particularly to a linear cable-connector which connects the ends of a pair of cables such as electric power cables that supply electric power to various mechanical equipment.
In order to supply electric power to units that are separated by a long distance from the power supply, it is necessary to connect several cables together in series with a connector. Also, when these cables are laid outdoors, it is necessary to adequately maintain the water proofing of the connector for these pairs of cables. A linear cable connector that is used for this purpose has been disclosed, for example, in Japanese Utility Model Resistration No. 2579115.
FIG. 5 shows one example of the conventional linear cable connector that is e.g. presented in that disclosure. This linear cable connector 1 has a connection terminal 2 in the center in the middle part of the connector 1 in the axial direction. This connection terminal 2 is made of metal such as copper or copper alloy that has good conductivity, and it is formed in a cylindrical shape such that the outer diameter in the middle section is small while the outer diameter at both ends is large, and there are connection holes 3, 3 having a circular cross section and an opening on both ends in the axial direction. It is not shown in the figures, however there is metallic plate with good conductivity formed around the inner peripheral surface of these connection holes 3, 3 to form contact terminals in a well-known structure.
Moreover, a pair of cables 4, 4 to be connected have conductors 5, 5, and the portions on the ends of the conductors 5, 5 that are exposed from the insulating coverings 6, 6 of the cables 4, 4 are securely connected to the base ends of plugs 7, 7, and connection tubes 8, 8 are formed on these base ends. These plugs 7, 7 are formed in a cylindrical shape from a metal having good conductivity, so by compressing the connection tubes 8, 8 inward in the radial direction after the ends of the aforementioned conductors 5, 5 have been inserted into these connection tubes 8, 8, they are securely fastened to the ends of the conductors 5, 5. Also, the tip ends of the plugs 7, 7 are inserted in the respective connection holes 3, 3, and make contact with the connection terminal 2 by way of the aforementioned contact terminals. The portion from the end of the insulating coverings 6, 6 to the base end of the plugs 7, 7 is covered by the base half of internal semiconductive layers 9, 9. The tip ends of these internal semiconductive layers 9, 9 are cylindrical-shaped sections 10, 10, and there are ring-shaped gaps formed between the inner peripheral surfaces of these cylindrical-shaped sections 10, 10 and the outer peripheral surfaces in the middle of the plugs 7, 7.
Moreover, the center component 18, made of an insulating material such as synthetic resin, is formed by molding such that it covers all the way around the circumference of the connection element 2. The inner diameter of this center component 18 is small in the middle portion and large on both ends. This center component 18 is joined with the aforementioned connection element 2 such that they do not shift each other. The outer peripheral surface of this center component 18 is tapered in a direction such that the radius becomes smaller in the direction toward both ends, and the center section has a cylindrical surface. In addition, a pair of engagement protrusions 11, 11 with trapezoidal cross-sections are formed all the way around the center section such that they are separated from each other in the axial direction.
Furthermore, insulating layers 12, 12 made of synthetic resin or the like are formed around the ends of the cables 4, 4, around the internal semiconductive layers 9, 9 and around plugs 7, 7, respectively. The inner peripheral surface on the tip half of the insulating layers 12, 12, as well as the inner peripheral surface of the cylindrical sections 10, 10 formed on the tip half of the internal semiconductive layers 9, 9 are conical concave tapered surfaces that come in close contact with the outer peripheral surfaces of both ends of the aforementioned center component 18. Also, external semiconductive layers 13, 13 made of an elastic material such as rubber are formed around these insulating layers 12, 12. These external semiconductive layers 13, 13, the insulating layers 12, 12 and the internal semiconductive layers 9, 9 come together to form insulating tubes 20, 20.
Also, the portions that protrude from the tip ends of the insulating layers 12, 12 on the tip ends of the external semiconductive layers 13, 13 are fitting tubes 14, 14. Engagement grooves 15, 15 that are formed on the inner peripheral surface of these fitting tubes 14, 14 fit tightly with the aforementioned engagement protrusions 11, 11. In addition, the outer peripheral surfaces of these fitting tubes 14, 14 are held by retaining bands 16, 16 such that the engagement grooves 15, 15 and the engagement protrusions 11, 11 do not accidentally come apart. Furthermore, by winding insulating tape between the base ends of the external semiconductive layers 13, 13 and the outer peripheral surfaces of the cables 4, 4, insulating coverings 17, 17 are formed. It is possible for the formation positions of the engagement grooves 15, 15 and the engagement protrusions 11, 11 to be opposite, as shown in FIG. 6.
In the case of the prior art construction described above, disassembly and reconnection are simple, however, water proofing is not always adequate. In other words, when the linear cable connector 1 is installed in a location where it is exposed to wind and rain, rain water that enters the connector 1 from the pair of abutting surfaces of the fitting tubes 14, 14 passes through the small gap between the inner peripheral surface of the insulating layers 12, 12 and the outer peripheral surface of the center component 18, and gets inside these insulating layers 12, 12, and there is a possibility that it will cause poor insulation.
Taking the above problem into consideration, the objective of this invention is to provide a linear cable connector that is constructed such that it can be disassembled or reconnected easily, and such that it is capable of maintaining stable insulating performance over a long period of time even under severe conditions of use.
Similar to the linear cable connector described above in the prior art, the linear cable connector of this invention comprises: connection terminals that are made of conductive material and formed with connection holes on both ends in the axial direction that open up on both ends; plugs that are made of conductive material and that have tip ends inserted into the aforementioned connection holes, and base ends securely fastened to the ends of conductive members forming a pair of cables to be connected; a center component that is made of insulating material and that is provided all the way around the aforementioned connection terminals such that it covers the connection terminals on the circumference thereof; and a pair of insulating tubes that are provided around the ends of the cables and around the plugs, such that the both ends of the center component can be freely inserted into the openings on the respective ends. Moreover, the opening ends of this pair of insulating tubes are joined together at the middle section of the center component.
Particularly, the linear cable connector of this invention comprises side flanges that are formed all the way around the opening ends of the insulating tubes. These side flanges of the insulating tubes are fastened together with a seal ring located between the abutting flange surfaces.
Moreover, as necessary, a middle flange can be located generally around the outer peripheral surface in the middle of the center component such that it protrudes outward in the radial direction. The aforementioned middle flange can then be held between the abutting surfaces of the side flanges on both of the insulating cylinders with seal rings interposed, and further, the side flanges on both of the insulating tubes can be fastened to the aforementioned middle flange.
The linear cable connector of this invention, constructed as described above, can be effectively sealed with a seal ring between the abutting surfaces or pair of side flanges on the insulating tubes,.or with seal rings between both surfaces of the middle side flange and the side surfaces of the side flanges on both of the insulating tubes. Also, disassembly or reconnection can be performed easily by separating or connecting the side flanges on the insulating tubes, or by separating or connecting the surfaces of the middle flange from the side surfaces of both of the side flanges on the insulating tubes.